2 o a l A g e
McGr a w- Hi l l
Pu b l i s h i n g Co m p a n y, In c. J a m e s H. McGra w, President E d w a r d J . M e h r e n , Vice-President
D e v o t e d to the Operating, Technical and Business Problem s o f the
Coal M in in g In d u stry
Jo h n M . Carmody
E ditor
Volume 33 N e w Y o r k , A u g u s t , 1928 N u m b e r 8
Coal Versus Oil
I O W as are the prices of coal it, neverthe- j less, has to face in places a keen compe
tition with oil. Fuel oil is being sold under a three-year g u a ra n tee to the U . S. Shipping Board a t N e w Y o rk City a t 92c. p e r barrel, equivalent to a price of $3.93 a ton fo r bitu
minous coal o f goo d g rad e delivered at tidewater. D edu ctin g a bunkering cost of from 18 to 25c, th a t would adm it of a price of $3.75 to $3.83, assuming th a t coal were as easy to fire as fuel oil. T h is price m ight indeed be m et in small volume with slack, but with hand firing fo u r times and with pulver- ized-coal firing th re e times as many men are required a n d there are additional costs fo r equipment, coal crushing, bunker space and upkeep.
C O N S E Q U E N T L Y , despite all the suc
cess with the Steam er “ M e r c e r ,” pulver
ized coal will have h a r d sailing till the price of oil once m ore increases. W h e n the experi
ments on the “ M e r c e r ” commenced the price of oil was $ 1.80 a b a rre l here and m ore across the seas. But the price has sagged so much th a t the U . S. Shipping B o a rd will use more oil than coal.
I T IS a m a t te r f o r encouragem ent th a t de
spite decreasing oil costs the Shipping Board will continue its experiments. I t is testing o th e r pulverizers an d bu rn ers and in
tends before lon g to turn two m o re ships to pulverized coal. Few, if any, believe th a t oil prices will continue a t th eir present low' level; few, however, ever suspected they would fall so low.
B U T outside of tidew ater, coal does not have the difficult competition it has on the coast. W h e n oil has to be tra n s p o rte d by rail it usually finds itself, even to d ay with its present low prices, on an in ferior footing to coal. T h e tendency away fro m fuel oil has been m arked. T h e railroa ds have steadily reduced their oil consumption in recent y e a rs;
so also have the public utilities. T h is has continued th ro u g h the present y e a r with the three m onths of record with the railro a d s and with fo u r m onths of reco rd w ith the public utilities. In 1927 the la tte r used 28 per cent less oil th a n in 1926.
O Y E R 3 6 8 ,000 ,0 00 ba rre ls o f dom es
tic fuel oil are still used, displacing over- 86,0 00,00 0 tons of coal, 4 2,0 00 ,00 0 b a rre ls of foreign oil displacing 10,000,000 tons of coal and a trillion cubic feet o f n a tu ra l gas, the equivalent of about 4 3,0 0 0 ,0 0 0 tons of coal. T h e industry should be p r e p a re d to show the m etho d of burning coal t h a t will give the g re a te s t h eat with the least quantity o f fuel consumed. T h e n th ere will be no tendency to w a rd oil and n a tu r a l gas. T h e public utilities, which are good judges o f eco
nomical combustion, have shown by th eir tre n d t h a t oil burning does not pay a t prices to d ay and h ith e rto ruling.
T O D I S P L A C E fuel oil and gas nearly 139,000,000 tons of coal will be needed each year. Surely this is w o rth y of the care
ful consideration of the industry. C annot some of this business be recovered by burning coal m ore efficiently?
Unloading Coal at Buenos Aires
From a Painting by Benito Quinquela M artin
How Anthracite
Attacks Sales Problems
M
e r c h a n d i s i n g, alreadya m ajor issue as a result of post-war changes in the Pennsylvania anthracite set-up, has been thrust to the front as the out
standing problem of the industry since the long strike of 1925-26. During the war years and, to some extent, in the years immediately following, “the market question” intruded so covertly that the industry as a whole seemed hardly conscious of its existence. The problem was still largely one of ap
portioning tonnage among eager buy
ers whose demands were of such vol
ume that it obscured the effects of competitive inroads close to home and declining sales in distant markets.
As these effects began to be better understood, however, there was an increasing interest in the merchandis
ing phases of the industry. This was first noticeable perhaps in a concen
trated drive to establish No. 1 buck
wheat as a domestic fuel—a drive forced upon the producers by the col
lapse of the m arket enjoyed by the steam sizes during the w ar and the mtensified competition from cheaper fuels. Pea, an uncertain quantity
By Sydney A. Hale
M anaging E ditor, Coal A g e
since its elevation to domestic rank in 1912, also grew more than usually troublesome. An attem pt was made to meet general criticism of sizing and standards of preparation for the larger coals.
The 1925-26 strike gave a tempo
rary setback to the expansion of an industry merchandising program be
cause the heavy buying which fol
lowed the resumption of operations lulled some producers into a false sense of security. But the production record of last year furnished an effective alarm clock. In 1927, the anthracite breakers loaded only 68,- 465,537 net tons of coal for ship
ment— the smallest tonnage, barring the strike years of 1922 and 1925, shipped from the breakers since 1909.
C
O M P A R E D with 1924. the year immediately preceding the big 1925-26 suspension, the 1927 breaker shipments showed a decrease of 7,- 237,805 tons, or 9.56 per cent. If sizes below pea are excluded, the decrease was 7,625,350 tons. Including local sales, steam shipments and dredge and washery product the de
crease under 1924 was 6,749,482 tons.
To a large extent this decline may he attributed to the competitive in
roads made by electricity, gas, fuel oil, bituminous coal, coke and foreign fuels. A t the present time electricity for home heating is a m inor fa c to r; gas is expanding but is still in the luxury class. Fuel oil is a very active com
petitor and promises to continue so for some time to come. Competition with foreign fuels is confined to the Canadian m arkets and to New E ng
land seaboard cities, principally Bos
ton and Providence and their en
virons. Bituminous coal and coke loom largest. From the standpoint of tonnage, bituminous coal leads, but coke is tne more dangerous competitor because 0 1 the growth in public- utility owned byproduct plants.
The decline in 1927 shipments and local sales when compared to 1924 figures indicates that competitive fuels have held approxim ately 50.19 per cent of the business throw n their way by the 1925-26 strike. T his per-
Axigust, 1928 — C O A L A G E 467
centage is based upon figures on in
creased sales of competitive fuels for domestic heating in 1925-26 published by the U. S. Bureau of Mines (T ryon and Bennit, “A nthracite in 1926,” pp.
3-7). T hat study estimates that hard coal consumers in those two years were compelled to use the equivalent of 27,100,000 net tons of competitive fuels to make up a deficit of 25,000,- 000 net tons of anthracite.
T
H E increase in sales of competitive fuels in 1925 and 1926 over 1924 was divided as follow s: Am eri
can briquets, 674,000 net to n s ; foreign briquets, 130,000; European anthra
cite, 961,000; byproduct coke for do
mestic heating, 3.516.000; beehive coke, 499,000; gas-house coke, 500,- 000; foreign coke, 320,000; fuel oil, the equivalent of 3,500,000 to n s ; bitu
minous coal, 17,000,000 tons.
These gains, of course, directly support one of the principal explana
tions advanced for the increasing difficulties in the m arketing of an
thracite—insecurity of supply. In terruption in supply of hard coal is one of the m ajor counts in the popu
lar indictment of the United Mine W orkers. D uring the ten years ended Dec. 31, 1927, the anthracite mines worked 2,452 days out of a theoreti
cal full-time 3,040 days. During that same period strikes were respon
sible for the loss of 371 days, or 12.2 per cent of possible full-time, and other causes, 217 days, or 7.1 per cent.
The record in the big strike years naturally is much worse. In 1922, strikes and lockouts caused a loss of 138 days, or 45.4 per cent of the pos
sible running tim e ; in 1925 the strike loss was 103 days, or 33.9 per cent, and in 1926, 41 days, or 13.5 per cent.
T hat these losses have given impetus to the sale of competitive fuels is a m atter of common knowledge. The menace frequent strikes held for the industry was one of the moving con
siderations in the long-term agree
ment of 1926.
T
H E R E are, however, two other factors which have contributed in no small measure to the increased sale of competitive fuels in anthraciteconsuming territory. Price has played its part with consumers compelled by circumstances or inclined by nature to weigh expenditures carefully.
But the allure of convenience prob
ably has made a still greater appeal and has robbed anthracite of some of its most desirable customers. The gas man and the fuel-oil distributor have laid great emphasis upon this
point and the latter appears to have led many householders to believe that automatic heat control was peculiar to oil-burner installations. This is a push-button age, and the competitors of hard coal have not been slow in capitalizing upon that fact.
These two factors—price and con
venience—have worked together to increase the potency of complaints against quality and preparation of anthracite shipped to the domestic consumer. T h at irresponsible agen
cies took advantage of the demands born of the war-time and strike crises in supply and sold tonnage the qual
ity of which would have shamed a respectable bootlegger is openly ad
mitted in the industry. T hat more reputable producers at times have per
mitted the loading of coal substandard in preparation or sizing likewise can
not be denied.
These sins have been so magnified in the public mind that the average domestic consumer of coal ascribes all his heating ills to poor or imperfectly prepared fuel. And with competitive fuels available and their use made easy there are many householders who take an unholy delight in an
nouncing their release from the thralldom of anthracite. T h at the dash for freedom often has been taken without the householder really knowing what he was trying to escape has not always helped the an
thracite industry.
T
H A T the m ajority of the anthracite operators are not unmindful of the seriousness of the situation confronting the industry is shown in the present trend of executive think
ing. These operators have a clear picture of the difficulties to be over
come and are moving in concert and as individuals to meet them. A t the same time there still remains an un
comfortable fringe of optimists who are waiting fo r God and the weather to restore hard coal to its war-time position. Fortunately, this minority is not large.
The head and front of the indus
try ’s group attack upon its merchan
dising problems is the Anthracite O perators’ Conference. The Confer
ence, representing both the old-line companies and the independent pro
ducers, is devoting a large part of its time to distribution questions. It has done much to improve retail contacts.
One evidence of this change was the creation of the office of vice-chair
man as a full-time job. F or this post the operators picked a man who had had wide experience in creating favor
able public relations for business en
terprises.
A
n o t h e r byproduct of this w work has been the greater participation of anthracite executives in the meetings of retailers. The “high h at” attitude which was criticized in these columns three years ago ( Coal A ge, Vol. 27, pp. 538-40) is vanish
ing. Public relations have been meas
urably improved.
Through its merchandising com
mittee the Conference enjoys a free exchange of opinion on common ques
tions of m arketing and what should be done to improve merchandising.
O ut of this committee recently came a recommendation upon sizing stand
ards to replace the standards adopted in the spring of 1925. The latest standards make a 1 per cent reduction in the permissible slate in egg, stove and nut, reduce the maximum under
size in nu t and pea and also establish screen standards for steam sizes.
T here is no change in the test-screen standards set up M arch 20, 192a ( Coal Age, Vol. 27, pp. 436, 477), but the new recommendations also definitely establish breaker - screen standards and maximum permissible wear upon such screens before re
moval. T he testing-screen mesh, per
missible oversize, undersize and im
purities are shown in Table I.
T he 1925 standards, hailed as a forw ard step at the time of their adoption, were disregarded by many producers despite the fact that it was Table I: Anthracite P r operation Standards
( R o u n d -m e s h S c re e n s)
1925 Standards v , 1928 Standards Testing Screen -— Maximum Permissible —* -— Maximum Permissible ■
Mesh Under- Under
Size Through Over size Slate Bone size* Slate A*one
Inches Inches Per Cent Per Cent
Broken... 4 * 3 * 15 2 2 15 2 ^
Esk... 3 2j 15 3 3 15 2
Stove... 2j IA 15 4 4 15 3 ’
N ut... 1ft fi I5f 5 5 10 4 >
Pea... H i 15 71 7i 10 7}
Buckwheat! .. . A A
Ricet ... A A
Barley!... A A Boiler... A A
* Permissible oversize, broken or buckwheat inclusive, a maximum of 5 per cent, t Plus not more than 5 per cent unavoidable breakage.
! Not covered in 1925 standards.
468 C O A L A G E — Vol.33,N°-8
stated at the time of their promulga
tion that 98 per cent of the tonnage had agreed to the specifications. R e
cent inspection tests show some ship
ments of nut and pea leaving the breakers with as high as 38 per cent oversize and the undersize down to 5 and 6 per cent. T he breakdown of the 1925 standards while helping to improve the quality and preparation from some collieries left the situation badly confused. I t is the hope of the operators that general acceptance of the new standards will result in greater uniform ity without degrading quality or preparation, which at pres
ent is winning high praise.
Through the Conference and its subsidiary organization, the A nthra
cite Coal Service, some progress is being made with m anufacturers of heating equipment for the home.
Until recently the pronounced apathy of many of the makers of standard furnace equipment has been one of the most discouraging obstacles en
countered. T he story is told of one manufacturer who ignored requests for a fuel engineer and when finally cornered sa id : “W hy, we have no engineers. The only change in pat
terns or design in our product since 1890 has been in scroll w ork.”
W
H IL E this represents an extreme case, it is a fact that many manufacturers have appeared very in
different to the possibilities of experi
mentation along the lines of more efficient and mechanized combustion in the home. T he use of buckwheat in ordinary furnaces, for example, was blocked because m anufacturers showed no interest in supplying a grate at an attractive price. T his in
difference is breaking down. A t the same time the m akers of some of the special equipment for burning buck
wheat are pushing sales more vigor
ously. Much, however, yet remains to be done both in sales promotion and in equipment design. T he im
portance of the equipment question has been clearly established by in
spections made of heating plants of the domestic consumer. In the case of one organization, out of 6,000 in
spections made on complaints against coal quality, it was found that 98 per cent of the complaints actually were due to the condition of the equip
ment. And yet it seldom occurs to the householder when he is unable to heat his home properly that his , furnace may be at fault.
Generally he is like the professional man who was at a dinner party last fall at which an executive of one of
the large sales agencies also happened to be a guest. The professional man, with some glee, told the coal man how sorry he felt for the industry with its problems of mining and try ing to sell inferior fuel, but added that his grief was not great enough to make him continue to use coal—
not when the furnace that once used 12 tons now ate up 18 tons without heating the house. H e was going to install an oil b u rn e r!
S
t a t e m e n t s that sizing and preparation of anthracite never were better were received with polite incredulity. The professional man was willing to concede, however, that, if he could get old-time satisfaction out of his equipment he would continue on coal. Thereupon the coal man asked him to submit to an eight- question “intelligence test.”
“W h at make of car do you drive?”
began the inquisitor.
T he professional man named it.
“H ow often do you have it gone over ?”
“Twice a year as a m atter of rou
tine and more frequently when neces
sary.”
“How often do you have your car
buretor adjusted?”
“Twice a year or more.”
“W hat brand of gas do you buy ?”
The name of a well-advertised brand was promptly given.
“W hat is the make of your fu r
nace ?”
The professional man didn’t know.
“ H ow often do you have it gone over?”
“Do you have to give your furnace attention?” exclaimed the profes
sional man in surprise.
“H ow often do you adjust its carburetor ?”
T he professional man explained that his was an old furnace without any such modern improvement and the coal man countered by telling him the dampers served the same purpose in a furnace as a carburetor in a car.
“W h at brand of coal do you burn ?”
“W hy, just coal.”
And "subsequent inspection proved that all th at was w rong was an ac
cumulation of soot which was effec
tively insulating the heating plant.
A
N O T H E R activity which the l Conference is pursuing is research. T his is one of its latest undertakings. Instead of an ambi
tious pre-planned program , however, the operators are wisely seeking coun
sel of recognized combustion authori
ties in an endeavor to determine
along what lines actual, practical re
search may be most profitably under
taken. One question which probably will receive consideration is the pos
sible use of small coal in gas m anu
facture to recover the m arket once held by large anthracite.
T he most active agency of the op
erators in the direct promotion of merchandising developments is the Anthracite Coal Service. This or
ganization, the offshoot of an unsuc
cessful venture in the promotion of a specialty heating device, has grown from one man to 75. Originally de
voting most of its energies to holding business for the steam sizes of an thra
cite, demand has forced the Service to give more and more attention to retail distribution problems.
O ut of this w ork has developed the combustion schools for retailers.
These schools train the employees of the retail coal m erchant in the funda
mentals of combustion, plant inspec
tion and servicing the consumer.
S tarting at Trenton, N. J., since Ja n uary, 1927, the A nthracite Coal Serv
ice has trained 1,261 representatives of 769 retail companies in 46 commu
nities and is now' conducting classes in 24 cities where nearly 600 employ
ees of over 300 dealers are enrolled.
I
N C IT IE S where the training course has been completed or is well advanced co-operative newspaper advertising on a 50-50 basis is open to the dealers. A monthly pamphlet, The Anthracite Salesman, featuring methods of retailers in merchandising anthracite and suggestions fo r in- increasing and im proving business, goes to 12,000 retailers. A nother publication, The Anthracite Coal Service Magazine, goes to 10,000 engineers, architects and building owmers in an effort to impress upon them the advantages of hard coal. In addition the engineering corps is a t the call of retail distributors.T his spring a group of companies, including a number of independent producers and all but two of the fo r
m er railroad coal companies, launched a co-operative newspaper advertising campaign in the large cities in the anthracite-consuming territory. T his is being followed up by a 24-sheet poster billboard campaign started in June. T he group in this venture are advertising their product as “C E R T - I-F ID E A N T H R A C IT E .” Retail distributors are furnished metal signs featuring this name and also stickers to place on delivery tickets. A p
proxim ately $500,000 was appro
priated for the first year’s campaign.
August, 1928 — C O A L A G E 469
M ech a n ica l lo a d in g
IVith A.C. Power Meets Test at Francisco
T
H E loader has sufficient traction to force its nose well under the loose coal and to load it without the aid of the pick cylinder. W ith the picks at the lowest position and moving upw ard against the coal the machine can dig its way into the standing coal and if the picks are raised and reversed in motion it can pull the standing coal down onto the conveyor. Five feet or slightly less is the lower limit of
470 C O A L A G E — Vol.33, No*
W
H E N mechanical loading was being considered for the Francisco M ining Co.’s No. 2 operation, about seven miles east of Princeton, Ind., J. R. Henderson, manager, and the other officials agreed that the system adopted must first show success with the old tried and proved mining system. There would be too much risk involved in going to a new plan of working coincident with a change to mechanical loading.
The new Sullivan Class M C2 load
ing machine was selected for a trial, and the first one was installed Aug.
25, 1927. L ater another of the same type was purchased. Operation d u r
ing the first few months could not he
By John Moshey
M ine Superintendent Francisco M ining Co.
Francisco, Ind.
classed as satisfactory, but in January the situation was changed and succes
sively better averages were made in February and March.
The mine is in the No. 5 vein, which lies practically level and under a uniform cover of 300 ft. The aver
age coal thickness is ft., and about 22 in. from the top there is a 1-in.
parting of carbon shale. The bottom
Loading H ead-M achine in a Breakthrough
is a fireclay which becomes soft if wet, but fortunately, considering this condition, the mine is quite dry.
Above the coal is a slate which makes a fairly good roof. Because the mine is dry. and gassy, all entries are kept thoroughly rock-dusted.
T he present system is to drive 24-ft. rooms 250 ft. deep on 40-ft.
centers and to leave the pillars. The track is placed in the center of the room and two rows of props are set on each side to about 14 ft. of the face. T he coal is undercut to a depth of 6 ft. with a shortwall machine, making each cut yield about 36 tons.
The mine operates with union labor.
Because of the ability of the loading machine to dig as well as load, the coal is not shot so hard as to roll it all down free of the face; in
stead, some of the cut stands. The loader is mounted on crawler treads and carries at the front end a rever
sible pick cylinder which can be low
ered to the scoop nose, raised to a position about 6 ft. from the floor, or operated at any interm ediate position.
height for convenient operation of the size machine which we use.
To insure good operating voltage without heavy expense for d.-c.
feeders, a.c. was chosen for the load
ing-machine power distribution. It is my understanding that few other mines use a.-c. loading machines.
Our experience to date has convinced us that the a.-c. system is entirely satisfactory and makes it easy to keep full voltage on the motors.
The loading-machine motors are wound for 2 2 0 -v o lt three-.phase 60-cycle power. Feeders carrying 2.300 volts enter the mine through drillholes kept within 3,000 ft. of the loading machine. T he change to 220 volts is made in a truck-m ounted sub
file 220-volt line to 1,200 ft. except where local conditions make it advis
able to extend the distance to as much as 2,000 ft.
W ith hand loading three shotholes are drilled per place, but with me
chanical loading the number has been increased to six, yet the total amount of explosive used per place is less—
34 to 4 lb. instead of 5 to 6 lb. Three snubbing shots are fired before shoot
ing the top holes, but the coal loosened by the snubbing shots is not moved prior to firing the upper shots. P e r
missible explosive is used. The charges are H sticks each in the top rib holes and one stick each in the others.
The two machines work a com-
Productions per machine are indi
cated by the following averages: F o r the 23 working days in February one machine produced 202 tons per day and another 212 tons. Peaks for each were 274 tons and 237 tons re
spectively'. F o r the 24 working days in M arch the average for both was 239 tons per machine per shift.
Tim e studies were made for sev
eral days in order to determ ine and classify the lost-time items. O n a day when one machine loaded 102 cars, or 257 tons, the total of 8 hours was taken up as follows: Loading coal, 39.1 per cent; shifting machine, 8.1 per cent; car changing, 32.5 per cent ; moving machine, 7.2 per cent ; cars oft' track, 0.6 per cent; delays gathering m otor, 1 per cent ; delays parting motor, 8.5 per cent ; power off, 0.1 per cent; machine disability, 0.2 per cent, and other delays, 2.7 per cent.
station consisting of three 25-kva.
transformers and an oil switch.
These items of equipment are housed in a box or tank of ¿-in. steel, the cover of which will fall closed in case of fire. T he 2,300-volt rubber- sheathed cable feeding this portable transformer bank is carried in an air course from the bottom of the drill
hole. Three No. 4 /0 single-conduc
tor rubber-covered double-braid wires hung on knobs along the ribs form the 220-volt secondary distribution.
The transform er truck is moved at intervals so as to hold the length of
Slccl B o x Containing T ransform er
M achine on the M ove
plete panel, including room necks and entries. W ork of the loading machine crew, consisting of two men.
is made less irksome by a practice of sprinkling the face after shooting, so that very little coal dust gets into the air during operation of the loading machine. The sprinkling is done from a car-mounted tank 29 in. in diameter and 74 ft. long. One tank full of w ater sprinkles two places.
Care must be exercised not to use too much water because an excess will cause trouble for the loading machine bv softening the bottom.
T
H E crew per machine, including all operations necessary to deliver the coal to the main-haul parting, figures 1.34 men. Nine men are concerned directly with each machine and nine other men split their time be
tween the two machines. W e know that it is possible to get at least 50 tons more per machine by adding to the crew, but as yet we have not determined if this would be an eco
nomical step.
An im portant feature contributing to the success of the loading machines is the use of a service truck on- which is carried a barrel of lubricating oil, jacks, repair tools and a few common supplies. A heavy vise is mounted on the top deck of the truck. T he night repairman takes this truck with him to each loading machine. H is c h ie f' dutyr is oiling and inspection, but by having the truck with him he is pre
pared to make a thorough job of any repairing found necessary'. The total Repair T ru ck W ith Barrel at One E nd
and Vise at the O ther
August, 1928 — C O A L A G E 471
time per day put in on oiling, inspec
tion and repair averages about 5 hours per machine.
Each loader is tended by a storage- battery locomotive which shifts cars to room breakthroughs. One track, located in the center room, serves as the outlet for each group of three rooms. From the main-haul parting to the rooms the cars are handled in trips of five by mules or cable-reel locomotives.
Now that the loading machines have proved successful without change in the m ining system we ex pect to try driving rooms 33 ft. wide and double track them so that little time w ill be lost in car changing.
Roof characteristics demanding the placing of center props too close to the face may block this method.
W ith hand loading approxim ately one-half of the 1-in. parting was thrown out at the face. W ith the present system of mechanical loading all of this has to be removed at the tipple, which means that men had to be added to the picking force.
The percentage of screenings in the machine-loaded coal is practically the same as that from hand loading.
There has been a slight decrease in the proportion of 6-in. lump, but the exact amount has not been deter
mined. The coal is prepared in a modern five-track steel tipple equipped with three picking tables, the conveyors of which extend over the respective loading booms.
Compared to hand loading we have determined that with machine loading the cost of coal delivered onto the parting is 25 per cent less. This takes into consideration all labor, supplies, powder and the in
terest and depreciation charges on the machine.
Loading fro m the Corner o f a 26-Ft. R oom
As a result of this saving and the experience to date with the Sullivan loading machine it is the plan of M r.
H enderson to put the whole mine on this type of mechanical loader as fast
B y H . G. T u r n e r
A ssista n t P rofessor o f Geology Lehigh U niversity, Bethlehem , Pa.
T
H E term “inherent ash” appears very frequently throughout the literature dealing with the constitution of coal. I t was originally used as a term to indicate a measure of the inorganic constituents of the plants from which coal was derived, but now its m eaning is very much in doubt. In some collieries it is used to indicate the ash afte r the coal has been freed from bone, slate and other mineral associates through com
mercial sink-and-float cleaning or other methods of washing. In the latter case the “inherent ash” would vary with the methods of cleaning.
The term “inherent ash” is entirely misleading even in its original sense, as we do not know exactly what in
organic compounds were in the coal- forming plants nor what their per
centage was. W hen trees like oak, beech and pine are burned, the ash is less than 1 per cent. Again, some of the living plants more closely re
lated to the ancient coal-forming ones, as, for example, some of the living tree ferns, club mosses, and horsetails, leave ash ranging from 3 to 11 per cent. In fact, it is chiefly through a study of the present plants that we are able to arrive at con
clusions regarding the composition of plants of the past.
Assuming, then, that coal-forming plants had an ash content from less
as m arket conditions justify an in
crease in tonnage. I t is quite likely that within a year or two the mine will be producing 3,000 tons of ma
chine-loaded coal per day.
than one per cent to over eleven per cent, how will this affect the “inher
ent ash” of coal-form ing plants?
I t seems clear that the “inherent ash” of coal-form ing plants cannot be the same as the so-called “inherent ash” of the resulting coal. It is generally believed that coal was formed by the accumulation and alteration, o f. vegetation in large swamps. T his vegetation lost a por
tion of its organic components, and while this loss was taking place, some of the inorganic m atter must have gone into solution in the swamp w aters; how much, we have no way of knowing. N either do we know what became of this inorganic matter.
If it escaped through drainage, which is poor in swamps, a great deal was lost. If it did not escape it must have accumulated until it was pre
cipitated from solution. During a later stage in the coal-forming proc
ess, this inorganic m atter must have been fu rth er changed; ju st how much and in what direction, again we do not know. Coal analyses" throw no light on the problem, for the ash given in them includes the mineral m atter in the form of sediment laid down with the dying plants, minerals carried in solution in the waters which flowed into the swamp, and m inerals deposited a fte r the coal was formed, as well as the doubtful factor of inherent inorganic materials of the original plants.
Since we have no way of knowing how much of the coal ash represents materials occurring as constituents of the plants from which the coal was formed, the term “inherent ash”
should either be dropped or given a definite meaning.
An alternative term is minimum ash and is defined as that portion of coal ash which is obtained from the inorganic m atter that cannot be re
moved from coal without chemical alteration of the organic coal sub
stances. T he minimum ash for every*
coal could probably' be determined by some standard method of fine grind
ing and flotation without destructive chemical treatm ent, and would indi
cate a limit of efficiency for the clean
ing method employed.
IN H E R E N T A S H a Misnomer
472 C O A L A G E — Vol.33,No£
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Why Not MINE COAL /// Illinois
By Retreating Long wall?
N MY previous article, entitled
“What Is T he M atter W ith Illinois?” which appeared in the July issue of Co a l Ag e, pp. 409-410, I showed that Illinois could recover its status if the coal lessors would allow the operators to remove entirely all the coal instead of a part of it, if the state would liberalize its laws requiring the driving of frequent crosscuts, if yardage for narrow work which is no longer justified be abolished and only 5c. a ton extra paid for such work, and if the m iner would cease to oppose the introduc
tion of mechanical appliances for loading and conveying.
There still remains the necessity for planning a system of operation that will permit full benefit from these concessions when obtained. I submit what is, I believe, an entirely new mining layout, and one peculiarly fitted to Illinois conditions if the four changes ju st advocated can be put into effect. The plan is shown in Fig. 4, and in modifications of the same in Figs. 1, 2, and 3. It provides
Fig. 1— Inclined Pillar Faces
By Oscar Cartilage
Consulting Engineer Charleston, IV. Va.
a greater length of working face in a given area than has hitherto been devised. Even with the coal faces set at a angle of 30 deg., as shown in Figs. 1 and 4, the actual pillar faces are 3,682 ft. long when the pillars are 100 ft. wide. Add to these pillar faces— 32 in number—the necessary narrow places to maintain an average tonnage, and a total of over 8,100 tons is possible from each day’s load
ing if the coal is 7 ft. thick and under
cut to an equal depth. And this from only one cut a day in each place.
Two or three cuts from narrow places could easily be made with good loading machines, but that is not pos
sible under laws which require that all blasting be done solely in shifts when only shotfirers are underground.
As this large output can be ob
tained from a relatively small terri
tory, operating costs will be greatly reduced. O f course, most of the older mines are incapable of han-
Fig. 2— Square Pillar Faces
dling such tonnages, but it is possible for them to m odify the plan to suit the>r conditions.
This system will simplify ventila
tion. Fresh aid traverses the haulage- ways and working faces and wastes out -over the abandoned gob. Stop
pings are few, and there are not many overcasts and doors to erect and maintain.
Haulage is reduced to the handling of cars en vtasse, which is the m ost effective method, and track has to be laid only in straight entries, with no room switches and with only an occasional crosscut switch to lay.
Tim bering is m ore expensive, but it is possible to recover cribs and props and use them over if proper attention is paid to this work. Collapsible props of the Lorain type should, and will, cause any Illinois roof to break when and where the engineer desires.
T he proposed plan is shown in Fig. 4 : From main entries, Z of which there may be two or more, cross-entries, y, are driven any con
venient distance apart, and in the pos- Fig. 3— Square Faces and D uckbills
August, 1928 — C O A L A G E
C O A L A G E — Vol.33.No-8 ition and num ber as shown if the full
member is to be operated. T he draw ing shows the inside entries 750 ft.
apart from center to center for each panel. From these cross-entries, y, narrow places are driven at right angles with any chosen centers, the draw ing showing them 112 ft. apart.
A R A L L E L IN G the crosscut entries, y , and exactly midway between the two inside ones, an entry, or pair of entries, is driven, X , from which long-pillar working faces 1, 2, 3, etc., are retreated in either dir
ection at an angle best suited to local
conditions. Each pillar preferably should be started a few feet behind the preceding one, form ing thereby a continuously advancing wedge. It is to be noted that the coal from each pillar face is carried inby.
In practice the required number of narrow places should be driven through, the work proceeding in both directions from y and X , and when the required number have been con
nected a cut would be made from the inby corner of pillar No. 1. W hen that pillar has been retreated the right
F ig. 4— A ll Coal R em oved Mechanically
distance— about 35 ft., as shown—
pillar No. 2 should be started in like m anner, and this proceeding should continue until the full number of faces is obtained. T he number of faces will, of course, depend on the line of roof break which had been previously determ ined to be the easiest to control
All conveyors, or track, if track is used instead of conveyors, are taken in the direction of solid coal, and workmen and equipment are pro
tected from roof falls by always being within the triangular space inside the line of roof, break.
L
IKE panels may be started fromj the main entries, Z , from time to time as necessity requires, and pillars supporting the cross-entries, y, will be recovered retreating when the wedge has advanced the limit, all track being taken up as the pillars are removed.
By driving the narrow intersec
tions, or rooms, through before start
ing withdrawal, pillars 1 and 2 (or more) may be started together in both directions from X and carried back on an even line. This has the disad
vantage that all of the equipment will have to be moved at the same time if conveyors are used for carrying the coal.
This system has these novel fea
tures: T hat the panel is split through the center by the entry X ; that by wide pillars the coal is withdraw n inby from that entry, the retreat being in two directions at the same time; that the pillars are draw n on the retreat, preferably in wedge fo r
mation, the angle chosen being that best suited to conditions; that the workmen and equipment are at all times on the escape side of the break line; that the combination of contin
uous advance with wide retreating pillars with faces at an angle gives the maximum tonnage that can be obtained from any given panel width.
|^ H E panels are ventilated in the A ordinary way, the air going up the middle cross-entry, y, and return
ing on the two entries on either side, so as to permit the conveyors to op
erate through crosscuts without inter
ference from stoppings. W here narrow places are driven beyond the limit allowed for crosscuts, auxiliary fans and flexible tubing are used to force air to the faces.
Fig. 1 shows the arrangem ent in de
tail at the loading point between pil
lars 6 and 7 when conveyors are used to transport the coal to the mine cars.
Conveyors A may be of the belt type, each 340 ft. long fo r the plan as shown and preferably should be of r'gid consruction with the frame mounted on wheels or rollers so that the conveyors can be pulled forward by a motor or winch whenever a pillar face is finished. T he same applies to Conveyors B, except that they are 100 ft. longer.
As each pillar in turn is finished the conveyors A and B are moved forward one pillar a n d . the transfer conveyors D are moved with them, making a new loading point each j'me. the process being repeated as long as the wedge advances.
/'~ 'O N V E Y O R D must have double the carrying capacity of A and B and should be constructed in movable sections, as it m ust be moved and re-erected in crosscuts about every 40 days if the pillars are 280 ft. long, as indicated. All other conveyors may be of the shaker type, of suit
able capacity for the work to be done.
Fig. 2 is like Fig. 1 except that the pillar faces are shown at right angles to the rooms.
Fig. 3 shows three pillars retreating together; cutting, shooting, loading and timbering, each being perform ed at the same time. Fig. 5 shows how the work may be advanced on one side and the other side brought back retreating, at which time the pillars and barriers would be recovered also.
Fig. 6 is an idealized scheme for room-and-pillar work where shooting and loading can be done on the same shift. It is then possible to take more than one cut out of narrow places and perhaps in rooms also. Rooms are turned off cross-entries and driven the full width of cut that can be made by a circle-cutting machine, the cut being at the bottom or any other place in the seam most suitable. In other cases the coal may be undercut by shortwell machines. W ide pillars are left between rooms, which are ex
tracted as rapidly as the w ork ad
vances.
S
FIO R T conveyors transport the coal to the cars. These, which are 70 to 80 ft. long, are designed to be of a length that will load four or five cars at one spotting. T hey extend alongside the track and are sup
ported between the first and second rows of props on the crosscut side and have side deflectors at the un
loading ends. Those shown in the drawing are of the shaking type with Duckbill loaders attached, but other
types of conveyors and other loaders also can be used to handle the coal.
Fig. 7 is a room section showing the conveyor ready to begin loading into the cars. I indicate the location of portable electrically driven air compressors which are intended to furnish the compressed air needed at the w orking faces for actuating the conveyors. A ir m otors are much cheaper in first cost than electric m otors intended for the same purpose.
It may be, however, that it would require too large a machine for prac
tical purposes, in which case the line could be broken up into more units, or, if that is not practicable, electric drives could be provided instead. As the compressors would be moved inby at stated intervals— every 580 ft. as shown—and on the mine "tracks, wheels should be provided for the machines so that they could be tran s
ferred easily and quickly.
T
H E ventilating current travels up the two right-hand entries and returns through the two at the left.This arrangem ent does away with all stoppings and only an occasional door, for crosscuts are not required between the middle entries except for haulage.
If four tracks are maintained the two inner ones will serve ideally as places in which gathering locomotives can store loads. T he track in the two outer entries may be taken up behind the compressors as the work progresses.
R eferring again to Fig. 4, it is apparent that only one wedge may be operated, but if two are advanced at the same time there should be five cross-entries y in the center and three on the sides.
Cribs or steel props may be used for breaking the roof, and interm e
diate tim bering will be done as neces
A<mst, 1928 — C O A L A G E 475
*:Duckbi/i loader
M ining m achine>,
Mining machine
-M otor
/J ig g in g 'conveyory
sity demands. The angle of roof break being in peculiar relation to the angled faces, excessive roof weight will be avoided at the w ork
ing faces, except, perhaps, at the points, and therefore power loaders, such as the Goodman, should be able to work with safety, especially if a thin strip of coal is left at the points.
The angled faces should be favorable also fo r the use of scraper loaders and fo r loaders operating on cater
pillar treads.
To prevent the coal from be
ing scattered when blasted, and to hold it in better position for load
ing, steel plates in lengths convenient for easy handling should be set on
Fig. 7— Feeding a Long Line o f Cars
mss//wws/v/w,.
S e c tio n -T h ro u g h A~A
T
redge against the inside row of props before the coal is shot down.
By indicating the use of shaking conveyors and Duckbill loaders I do not intend to indicate th at they are superior to others, for I do not know that they are. Scraper loaders and power shovels might do as well or Fig. 6—W ith T u rret C utters and D uckbills
Jigging conveyor
Crosscuts lo a d ed our by h a n d
P ortable a ir-etecrn c com pressor m oved fo rw a rd w hen te n rooms;7 a re w orked o u t ... ’
better, and in some cases the mine track might be laid alongside the face and the coal be hand-loaded with advantage.
Table 1— Equipm ent R equired for M echanisation
4 transfer conveyors D, each 50 ft.
long... $15,000 4 entry conveyors A, each 350 ft.
long... 68,000 4 entry conveyors B, each 450 ft.
long... 90,000 2 large shaking conveyors C, each
300 ft. long... 6,500 2 large shaking conveyors E, each
200 ft. long... 5,800 13 light shaking conveyors, each 100
ft. long with duckbill leaders at
tached, for entry work... 37,500 16 light shaking conveyors, each 150
ft. long with duckbill loaders at
tached, for narrow work... 49,300 34 room conveyors, average length
190 ft ... 80,600 32 face conveyors, each 120 ft. long
with duckbill loaders attached.... 92,800 1,000 mine cars, 4-ton capacity... 250,000 23 mining machines... 85,000 16 gathering locomotives... 90,000 6 main-line locomotives... 50,000 30 blower fans with flexible tubing... 10,000 25 portable electric drills... 9,000 12 doors, material for...
3 overcasts, material for... 6,000
16.000 ft.mine^trackmaterial 12,000
150 stoppings, material for... 40,000 40.000 ft. insulated copper wire... 3,500 15.000 ft. trolley wire...
Bonds, hangers, etc... 2,000
$1,012,500
All mining, shooting, conveyor moving, etc., with a fully mechanized layout, should be done on the night shift, except that loaders and other daymen should assist in moving equipment and in timbering roof during their spare time. All loading, conveying, hauling, etc., should be done on the day shift, and each place m ust be cleaned up and ready for the night crews, which crews must also have each place ready and the coal shot down for the next day’s- loading. Shooting will have to be done on third sh ift wherever the laws require that everyone except the shotfirers be outside when coal is shot.
Assum ing that we have a lay
out such as is depicted by Fig. 4 and that an agreem ent had been made between operators and miners to co
operate in handling mechanical equip- (T u r n to page 489)
C O A L A G E I N D E X — The index to volume 33 o f Coal Age, covering January to D e c e m b e r,
1928, inclusive, will be bound in the issue o f December n e x t .
C O A L A G E — Vol.33,No.8
Standard Equipment Slightly Modified Interlocks E-M ile Conveyor
Dumps 10 'diam. x574 'long fo r 55 m in e ca rs
DSÔ 'u n d er
MJF^^Meeders
¿ n a n or f
" " b e l t s 1
iSiS s
R iver tip p le,
I
N 1923 the H . C. Frick Coke Co., after extensive study and investigation, undertook the installation of what probably is the longest belt- conveyor system in the world. This installation, known as the Colonial Dock conveyor, carries coal from the mine through an underground tunnel to a loading dock on the M onon- gahela River, a distance of 22,930 ft.
The system was designed to trans
port 1,220 tons of coal per hour and consists of nineteen sections of 48-in.
belt running at 500 ft. per m inute and one section of 60-in. belt operating at 350 ft. per minute. The sections vary in length from 321 to 1,513 ft.
The electrical equipment consists of twenty wound-rotor type induc
tion motors varying from 50 to 175 hp. and twenty automatic starting and control equipments. The motors are of practically standard construction, so the chief problem was in laying out a control equipment that would fulfill the operating requirem ents and be sufficiently sturdy to withstand continuous operation w ithout undue attention and upkeep.
It was at once apparent that the chief feature of the control was to be a system o f . interlocking that would insure the proper sequence in starting and give adequate protection while running, to prevent the delivery of coal to a stopped section.
From a m anufacturing standpoint
control panel, together with the neces
sary rheostats, control transform ers and limit switches. Each of the con
trol panels contains a suitable oil- immersed prim ary contactor, the necessary secondary accelerating con
tactors, a solenoid brake contactor, control switches, control contactor and time-limit and current-lim it relays.
T N S T A R T IN G , the rotor resist- JL ance is cut out by the accelerating contactors, whose operation is con
trolled by a combination of time-limit and current-lim it relays. T he first two steps of resistance are of suffi
cient value to give comparatively low torque on the motor, thus allowing it to take up any slack in the belt and backlash in the gears w ithout exces
sive shock. These two points are actuated by time-limit relays, after which the m otor is accelerated to full speed by current-lim it control.
T he m aster control panel is located at the delivery end of the conveyor and contains the necessary devices to give complete control of the entire twenty sections. T he equipment on this panel consists of a double-pole control switch, a voltmeter arranged to indicate the starting of each con
veyor section, a start-stop push-but
ton station, an undervoltage protec
tive and control contactor, and a con
tactor for emergency shut-down.
T he general scheme of control is as
By F. R. Grant
Industrial E ngineering Departm ent, General Electric Co.
Starting Panel fo r One Section o f Colonial Conveyor
it was advisable, of course, to have the control equipment as nearly stand
ard as possible, and from an oper
ating and maintenance standpoint to keep it as simple as possible.
A fte r careful consideration, a con
trol system was laid out consisting of twenty combination prim ary and sec
ondary control panels and one m aster- Plan and Profile
o f Colonial Conveying S ystem
22.900' Track
16b e lts connecting No.20 conveyor w ith the tipple River Tipple and Barge
*»rge is lo a d e d b y 6 chutes w ith m o to r f /F
R iver Tippl
L o n g itu d in al S e c tio n Twin ro ta ry d u m p s a n d 54 apron
fe e d e rs a t p o in t A below p era ted g a te s
M onongahela f^iver I Mile 2Miles
L o n g i t u d i n a l S e c t i o n 3 Miles 4 Miles Dump p o in t A
August, 1928 — C O A L A G E 477
follows : T he various sections of con
veyor must start in sequence begin
ning with the delivery end of the system. In case of shut-down in regular service or because of loss of power, all motors will be de-energized simultaneously. In case of trouble with any one conveyor or motor which causes a shut-down of that p ar
ticular section, all conveyors between that section and the feed end will be simultaneously shut down, thus pre
venting coal being piled up on the conveyor section that is stopped.
The sequence of starting opera
tions is as follows : The operator depresses the start button on the m aster control panel. T his energizes the undervoltage and emergency con
trol contactors, which close and in turn energize the control contactor on motor control panel No. 1, which closes and energizes the prim ary con
tactor. afte r which the starting opera
tion is completed by means of the time-limit and current-lim it relays as heretofore explained. W hen thé last accelerating contactor on control panel No. 1 closes, it energizes the control contactor on panel No. 2, and this sequence is repeated until all twenty equipments are in operation.
A N E M E R G E N C Y control circuit
~ F \ is provided with a hand-operated switch located at each motor station.
Opening any of these switches de
energizes the emergency control con
tactor on the m aster panel, thus shut
ting down the entire system.
L im it switches located at each driv
ing station are actuated by a “belt slip ' device and are so arranged that, should the slip between the belt and the driving pulley exceed a certain am ount, the switch will open and shut down that conveyor and all those be
tween it and the feed end but will allow the others to run and clear
Interlocking Connections B etw een Sta rters o f Colonial Conveyors themselves ot coal. Provision is made so that any m otor in the se
quence can be operated independently for testing or adjustm ent.
Solenoid brakes were supplied for all motors, but it has been found in practice that they are required on only a few sections and accordingly have been disconnected on all sections where not needed. T his system was put into service in 1924 and has been in use ever since with practically no troubles from the electrical equip
ment. The system as a whole has proved to be a very efficient and eco
nomical means of transporting coal over comparatively long distances.
As a result of the experience gained with the Colonial Dock con
veying equipment, the H . C. Frick Co. in 1927 decided to install a simi
lar equipment approximately 24 miles long at its Palm er Dock. T his instal
One of the T w en ty Sta rtin g Equipm ents
lation consists of ' twelve conveyor belts, eleven of which operate in series to carry coal from the main 30-car dump to the tipple on the river bank, while the twelfth brings coal from the Palm er two-car dump and feeds the main conveyor at the fifth section.
T
H E first five sections consist of 60-in belt, the next six sections of 48-in. belt and the twelfth of 42-in.belt. The sections vary in length from 339 to 2,217 ft. and were de
signed to deliver 1,800 tons of coal per hour, 1,400 of which will come from the main dump and 400 from the Palm er dump.
T he power equipment consists of three 300-hp., three 200-hp„ four 175-hp., one 125-hp. and one 75-lip.
3-phase 60-cycle wound-rotor type induction motors with switchboards and control.
The control equipment in general is similar to that at the Colonial Dock;
the only changes were those made necessary by the particular problems not encountered in the previous in
stallation and the use of types of con
trol equipment which have been de
veloped since that time.
T he principal change in the control was the use of time-limit relays ex
clusively for acceleration instead of a combination of time-limit and cur
rent-limit relays. T he chief differ
ence in operating conditions is that the first three sections of the con
veyor operate on a very steep grade, making it necessary' to provide brakes to keep the belts from running back
ward if power should fail or if the system should be shut down with coal on the belts. It also was necessary to
(T u rn to page 4SI)
H igh voltag e lin e c o n ta c to r m o u n te d
b a ck o f m a in p a n e I Resistor
B ra ke solenoid core h e ld u p a n d re le a s e d b y
ia tc h s o le n o id m e ch a n ism solenoid coils F o r p a n e ls o th e r th a n H o./ c o n n e c t Ho. lb to Ho. /0, Ho. 3 to Ho. 9 a n d Ho. 5 to No. 3
on p re c e d in g p a n e I
. 'To 5 on n e x t p a n e l
\ To Ho.3 o n n e x r p a n e ! To Ho.JO o n n e x t lim it s w itc h
478 C O A L A G E — Vol.33, N o t
